Waterproof casing

Abstract

A waterproof casing including a casing body which has a substantial box-shape and a lid which openably closes an open portion of the casing body. The casing body end the lid include respective first peripheral walls butted against each other to thereby prevent the intrusion of water into a receiving space for electrical parts, and also include respective second peripheral walls which are spaced outwardly from the first peripheral walls to form a space around the first peripheral walls, and are butted against each other, so that each of the joint portion between the first peripheral walls and the joint portion between the second peripheral walls forms a waterproof structure which limits the intrusion of water. The two joint portions are offset from each other in a vertical direction, and drain holes are formed through a bottom portion of the second peripheral wall of the casing body so as to reduce the pressure of a high-pressure water stream within the space and also to discharge the water from the space.

What is claimed is: 
     
       1. A waterproof casing comprising: a casing body having a substantial box-shape; and   a lid for openably closing an open portion of said casing body, said casing body and said lid jointly defining a receiving space for containing electrical parts,   wherein said casing body and said lid include respective first peripheral walls which are butted against each other to thereby prevent an intrusion of water into the receiving space, and also include respective second peripheral walls which are spaced outwardly from said first peripheral walls to form a space around said first peripheral walls, and are butted against each other, so that each of a joint portion between said first peripheral walls and a joint portion between said second peripheral walls forms a waterproof structure which limits an intrusion of water.   
     
     
       2. The waterproof casing according to claim 1, wherein a first vertical position of the joint portion between said second peripheral walls is vertically offset from a second vertical position of the joint portion between said first peripheral walls so as to prevent water intruded through the joint portion between said second peripheral walls from splashing the joint portion between said first peripheral walls. 
     
     
       3. The waterproof casing according to claim 2, wherein said first vertical position is adjacent a bottom wall of said casing body while said second vertical position is adjacent a top wall of said lid. 
     
     
       4. The waterproof casing according to claim 1, wherein a distal end portion of said second peripheral wall of said casing body includes a projected edge portion projecting toward said lid and a flange extending in a thickness direction of said second peripheral wall of said casing at a region adjacent to the projected edge portion so as to receive an edge of said second peripheral wall of said lid, while a distal end portion of said second peripheral wall of said lid includes a groove for receiving the projected edge portion and an outer distal end wall forming the groove which is held in intimate contact with the flange. 
     
     
       5. The waterproof casing according to claim 1, wherein a projection is formed upright on a distal end portion of said first peripheral wall of said casing body, and is disposed centrally of a thickness of said first peripheral wall of said casing, and a groove for fitting on the projection is formed in a distal end portion of said first peripheral wall of said lid, and wherein a thickness of said projection is less than said thickness of said first peripheral wall of said casing. 
     
     
       6. The waterproof casing according to claim 5, further comprising a packing mounted in the groove formed in the distal end portion of said first peripheral wall of said lid. 
     
     
       7. The waterproof casing according to claim 6, wherein said first peripheral walls of said casing body and said lid are hollow. 
     
     
       8. The waterproof casing according to claim 1, wherein a drain hole for discharging intruded water is formed in a bottom portion of said second peripheral wall of said casing body.